The attenuation of sound in tissue is strongly frequency dependent, is a major acoustical property of tissue, and is a useful parameter for tissue characterization schemes. Research has shown that normal liver, pancreas, and spleen tissue can be differentiated on the basis of their frequency dependent attenuations and that cirrhotic liver tissue has almost twice the attenuation of normal liver tissue. It is also well known that malignant tumors are more highly attenuating than benign tumors which, in turn, are more attenuating than normal tissue. Moreover, normal, infarcted and ischemic heart tissue can be differentiated by measurements of frequency dependent attenuation.
The prior art does not teach any simple method or apparatus for the in vivo measurement of attenuation.
Accordingly, it is the principal object of the present invention to obtain accurate in vivo measurements of attenuation.
It is a further object of the present invention to measure in vivo attenuation simply and reliably.
Yet another object of the present invention is to utilize the frequency dependent nature of sound attenuation to determine sound attenuation.